Round metal parts are conventionally accurately sized after an initial turning operation by a subsequent grinding operation in order to provide the required tolerance for the application for which the workpiece is to be utilized. For example, universal joints for vehicle drives conventionally include a joint member having four round surfaces of cylindrical shapes that are coaxial about a central axis of the joint member and have different diameters. The largest round surface is utilized with a seal to provide sealing of the joint, while the next largest round surface supports a bearing that mounts the joint. Both of the two smaller round surfaces are subsequently formed with projections, the larger one with splines utilized to rotatively couple the joint and the smaller one with a thread used in securing the joint in position. Grinding of these round surfaces on such joint members is both time consuming and costly but has been necessary in the past to provide the required roundness for accommodating the seal and bearing utilized as well as for providing the required roundness prior to the spline and thread forming.
A cooperable pair of movable tools has also been utilized in the past to cold form noncylindrical workpieces. See, for example, U.S. Pat. Nos. 419,292, 446,934, 1,446,447, 1,469,174, 3,044,332, 3,466,918, 3,498,095, and 3,503,237 which disclose such forming.
Hot forming of an axle having round surfaces of cylindrical shapes with different diameters is disclosed by U.S. Pat. No. 458,685 wherein a pair of straight tools are moved rectilinearly on opposite sides of the hot axle to provide the forming operation.
U.S. Pat. No. 625,575 discloses a pair of straight tools that are moved rectilinearly to cold form a workpiece having a single cylindrical surface of a round shape.
Also, U.S. Pat. No. 2,825,251 discloses a pair of tools used to perform forming by holding one of the tools stationary and moving the other one with the workpiece between the two tools.